Featured Research

A recent University of Iowa study reveals a new immune defense mechanism in normal airways and may help explain why people with cystic fibrosis are particularly susceptible to bacterial lung infections. The findings also may point the way to new approaches for treating the disease.

Share This

A recent University of Iowa study reveals a new immune defense mechanism in normal airways and may help explain why people with cystic fibrosis (CF) are particularly susceptible to bacterial lung infections. The findings also may point the way to new approaches for treating the disease.

Related Articles

The UI study shows how two enzymes generate and use reactive oxygen species (ROS) to destroy bacteria in normal airways. The team also found that this process is defective in airway tissue and cells containing the CF gene mutation. The study is published in the Nov. 2 online issue of the American Journal of Respiratory and Critical Care Medicine.

"Among the host defense systems that we know of in the airway, at least in cell culture and tissue explants, this is one of the most efficient antibacterial system we have identified," said Botond Banfi, M.D., Ph.D., UI assistant professor of anatomy and cell biology and senior study author. "The findings suggest that one reason for CF patients' weakened innate immunity might be the absence of this natural oxidative host defense mechanism."

Banfi added that correcting the problem by reconstituting the oxidative system might represent a totally new approach for preventing the onset of bacterial lung infections that often become chronic and eventually fatal in CF patients.

Working with airway cells and tissues from rats, cows and humans, the UI team uncovered the oxidative system, which produces hypothiocyanite -- a highly effective antibacterial compound. Banfi and his colleagues, including Patryk Moskwa, M.D., Ph.D., a UI postdoctoral fellow and first author of the study, showed that one airway enzyme (Duox) makes hydrogen peroxide and a second enzyme (lactoperoxidase) uses the hydrogen peroxide to convert a small molecule called thiocyanate into the bacteria-killing hypothiocyanite.

The UI researchers also showed that the critical thiocyanate cannot be transported across airway cells with the CF mutation, which means that hypothiocyanite is not produced. In other words, without thiocyanate the oxidative antibacterial system breaks down.

These results suggest that thiocyanate may not be present in the airway surface liquid of individuals with CF. Banfi and his colleagues intend to test that hypothesis by comparing thiocyanate levels in airway surface liquid from CF patients and from healthy individuals.

Thiocyanate is naturally present in body fluids like blood and saliva. Despite its name and its chemical relationship to cyanide, thiocyanate is not toxic. Hypothiocyanite is also harmless to human cells and tissues, but the UI team found that it is extremely efficient at killing bacteria including those most commonly associated with fatal lung infections in CF patients - Staphylococcus aureus and Pseudomonas aeruginosa.

"If we could reconstitute thiocyanate concentrations in the airway surface liquid, perhaps using a nebulizer, it might boost host defenses in CF patients and help prevent bacterial lung infections," Banfi said.

In addition to Banfi and Moskwa, the UI team included graduate student, Daniel Lorentzen; Katherine Excoffon, Ph.D., associate research scientist; Joseph Zabner, M.D., professor of internal medicine; Paul McCray, M.D., the Roy J. Carver Chair in Pulmonary Research and professor of pediatrics; and William Nauseef, M.D., professor of internal medicine. Corinne Dupuy at INSERM in Paris, France also was part of the research team.

University of Iowa. "Newly Discovered Immune Defense May Be Impaired In Cystic Fibrosis Airways." ScienceDaily. ScienceDaily, 6 December 2006. <www.sciencedaily.com/releases/2006/11/061130191013.htm>.

University of Iowa. (2006, December 6). Newly Discovered Immune Defense May Be Impaired In Cystic Fibrosis Airways. ScienceDaily. Retrieved March 3, 2015 from www.sciencedaily.com/releases/2006/11/061130191013.htm

University of Iowa. "Newly Discovered Immune Defense May Be Impaired In Cystic Fibrosis Airways." ScienceDaily. www.sciencedaily.com/releases/2006/11/061130191013.htm (accessed March 3, 2015).

More From ScienceDaily

More Health & Medicine News

Featured Research

Mar. 3, 2015 — Adults over the age of 30 only catch flu about twice a decade, a new study suggests. So, while it may feel like more, flu-like illness can be caused by many pathogens, making it difficult to assess ... full story

Mar. 3, 2015 — No significant change in home habits of smokers have been observed in the aftermath of a ban on smoking in public spaces, researchers report. Greater inspiration to kick the habit likely comes from ... full story

Mar. 3, 2015 — Heart function has been associated with the development of dementia and Alzheimer's disease through a new study. Participants with decreased heart function, measured by cardiac index, were two to ... full story

Mar. 3, 2015 — Children of recently separated or divorced families are likelier to drink sugar-sweetened beverages than children in families where the parents are married, putting them at higher risk for obesity ... full story

Mar. 3, 2015 — Gastric bypass and similar stomach-shrinking surgeries are a popular option for obese patients looking to lose weight or treat type 2 diabetes. While the surgeries have been linked to a decreased ... full story

Mar. 3, 2015 — Most people consume more salt than they need and therefore have a higher risk of heart disease and stroke, which are the two leading causes of death worldwide. But a new study reveals that dietary ... full story

Mar. 3, 2015 — Twice as many children born to mothers who took antibiotics during pregnancy were diagnosed with asthma by age 3 than children born to mothers who didn’t take prenatal antibiotics, a new study has ... full story

Mar. 3, 2015 — Although sedatives are often administered before surgery, a randomized trial finds that among patients undergoing elective surgery under general anesthesia, receiving the sedative lorazepam before ... full story

Mar. 3, 2015 — Pediatric otolaryngologists and surgeons are concerned with parents getting the wrong message regarding the safety/desirability of letting babies and young children eat peanuts to prevent them from ... full story

Featured Videos

Mom Triumphs Over Tragedy, Helps Other Families

AP (Mar. 3, 2015) — After her son, Dax, died from a rare form of leukemia, Julie Locke decided to give back to the doctors at St. Jude Children&apos;s Research Hospital who tried to save his life. She raised $1.6M to help other patients and their families. (March 3)
Video provided by AP

Looted and Leaking, South Sudan's Oil Wells Pose Health Risk

AFP (Mar. 3, 2015) — Thick black puddles and a looted, leaking ruin are all that remain of the Thar Jath oil treatment facility, once a crucial part of South Sudan&apos;s mainstay industry. Duration: 01:13
Video provided by AFP

Woman Convicted of Poisoning Son

AP (Mar. 3, 2015) — A woman who blogged for years about her son&apos;s constant health woes was convicted Monday of poisoning him to death by force-feeding heavy concentrations of sodium through his stomach tube. (March 3)
Video provided by AP

Related Stories

Feb. 18, 2015 — Potential targets for therapy for some adolescents with cystic fibrosis who develop advanced liver disease have been found by researchers. They found that those with liver disease had a different ... full story

Oct. 17, 2014 — Researchers have shown for the first time how bacteria can grow directly in the lungs of cystic fibrosis patients, giving them the opportunity to get tremendous insights into bacteria behavior and ... full story

July 13, 2012 — Scientists discovered a new strategy to help CF and COPD patients clear the thick and sticky mucus clogging their lungs, leading to life-threatening infections. The report shows the ... full story

Aug. 1, 2011 — The clinical outcome is improved if patients with chronic lung diseases such as cystic fibrosis are treated long-term with the antibiotic azithromycin. However, azithromycin treatment in patients ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.